Facile manufacture of silver(I) complex/multilayer graphene composite for dynamic adsorption desulfurization.

The cyclic triangular complex - silver (I) 4-nitro-3,5-bis(trifluoromethyl)pyrazolate (Agpz) with super π-acidity shows great potential in adsorptive desulfurization (ADS) as a novel adsorbent, however, it fails to work well in the continue flow adsorption study. In order to improve its dynamic adsorption performance, a composite has been prepared by mixing Agpz and multilayer graphene (MG) in methanol. Based on the results of characterization by FT-IR, XPS, SEM, and so on, the optimal mass ratio of Agpz:MG in the synthesis is 0.14, so composite obtained under this condition is labeled as Agpz/MG-0.14, in which the molecules of Agpz are uniformly distributed on the surface of MG via Ag∙∙∙C interactions and π-π stacking. The composite exhibits higher specific surface area than that of Agpz. Importantly, the column test proves the practicality of the composite - Agpz/MG-0.14 in continuous flow desulfurization with the enhanced dynamic capacity (4.0 mg S/g), in comparison with 1.9 mg S/g for graphene (C = 200 mg S/L for dibenzothiophene in iso-octane, m = 0.5 g, T = 298 K, v = 0.1 mL∙min). This work confirms the importance and advantage of the integration of functional coordination compound and suitable supporting materials for designing new type of high-performance ADS adsorbents.